Muriatic Acid Needs

[znelson]

I’m running into a similar problem as the following: Muriatic Acid Question

The pool is chugging muriatic acid weekly and I’ve yet to test and find the Ph lower than 8.2 which is the top of my scale. I’ve read a SWG exhibits this problem but never thought it could raise Ph so much so fast.

TA is 90, Ph is 8.0 currently (added acid yesterday), FC is only 1.0 at the moment but usually around 3.0. CYA is 80 and calcium is 300. Hose water Ph is 8.0. Also 100F temps everyday and tons of sun. We have to top-off about 2”-4” of water weekly which is lost to evaporation. So that all tracks with the comments on the referenced thread above.

It sounds like this is normal and we just counteract the Ph with acid. I’m going to apply more than usual in an attempt to get TA around 60 and see if that slows the Ph rise, and also test levels prior to filling up from the hose to isolate the effects from the SWG. Thanks!

 

[PoolStored]

SWCG is pH neutral.

High TA and low pH cause pH rise.

The addition of pH 8.0 water has some, but not large impact. Lower your pH in .4 increments, testing 30 minutes later, until your pH is 7.6. Let it rise to 8.0. Don't add more acid that what will lower pH by .4. Repeat until your TA is 60-80. Then STOP lowering pH to 7.6. It should be fairly stable between 7.8 and 8.0.

 

[znelson]

Thank you! I’m a little confused. Do you mean lower Ph to 7.6, allow it to rise to 8.0 max, then continue the downward adjustment (by .4 each time) until it reaches 7.6, rinse and repeat until TA is 60-80? Basically operate in the Ph 7.6-8.0 range with .4 adjustments each time until TA hits 60-80?

 

[dereksanders]

Yes. Your FC is extremely low for a CYA of 80.

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

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[PoolStored]

Thank you! I’m a little confused. Do you mean lower Ph to 7.6, allow it to rise to 8.0 max, then continue the downward adjustment (by .4 each time) until it reaches 7.6, rinse and repeat until TA is 60-80? Basically operate in the Ph 7.6-8.0 range with .4 adjustments each time until TA hits 60-80?

In general, do not attempt to lower pH in larger than .4 increments. If you have to lower from something north of 8, do .4, test 30 minutes later, add more if necessary.

I also mean you should lower your pH to 7.6, allow it to rise to 8. Then reduce to 7.6 again. When 60-80 TA, then let pH be at 7.8 to 8.0.

 

[znelson]

Got it! Thank you very much!

 

[Bperry]

Got it! Thank you very much!

Also be sure you’re reading the pH scale correctly. Seems lots of folks think it’s really higher than it is. Maybe post a picture for confirmation if you’re unsure.

 

[znelson]

Circling back on this .. I was able to slowly drop the Alkalinity to 60 and get the PH in range. That lasted about two weeks but now I’m seeing Alkalinity at 80 and PH at 8.0 again. It’s like a never ending battle and throwing acid in there every few days. Is a SWG really that effective at raising PH in a matter of 2-3 days? Is there anything else that could be doing this? I didn’t add water and there was no rain in the last 2 weeks since reaching optimal numbers.

 

[mknauss]

If the TA went up, you added something to do that. Typically that is fill water, though you said you did not add water.
Your signature shows Bromine. But you speak of a SWCG.

 

[znelson]

I didn’t add anything, that’s the concern, not even fill water.

I thought I edited that signature years ago

 

[PoolStored]

I didn’t add anything, that’s the concern, not even fill water.

Check your testing method, and clean your vials with rubbing alcohol. Bottle vertical, squeeze slowly so drops form and drop under their own weight. Wipe the tip of the R-009 with a wet paper towel before and between drops to eliminate static.

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